Szeto's career started off in Hong Kong TVB in 1984, wrote screenplays like Police Cadet (1984), File of Justice Season I & II (1992,1993). The most classical of all dramas is the At The Threshold of An Era I & II (1999-2000). The property developer, Hui Mun Piew, was the most controversial and talked about character online when the drama was aired over Chinese sphere countries.

His last screenplay is Motorway (2012), a film that featured Anthony Wong and Shawn Yue.